42 1/2ton

4

42 1/2ton

Member
Have a 29A in a 42 Commercial an have had a problem with an oil leak that is draining out the drain hole in bottom of bell housing. Pulled oil pan expecting to find the cover on the back of cam shaft leaking but clutch, flywheel, etc. dry and no evidence of oil running down from this cover.
Found the 1/2 inch oil return from bottom of main bearing cap was just a piece of tube with some kind of brass fitting kinda wedged in the drain pipe hole. Have a NOS drain pipe and will install when going back together but my question becomes can that incorrect tube have caused a leak? This rear main has the rope packing. The only obvious oil trails were under the rear main at the cork gasket. Also should this 29A have a rope packing or the slinger? Opened it up thinking it would be slinger.

Thanks for any info,
Ed
 
early ford blocks did not have a true seal, but had what is called a lambryth seal which is composed of two "slingers" that stopped the oil flow and channeled the oil back to the pan via the hole in the rear main cap and the short tube that comes out of it. the main problem we had with these was putting late model 80 lb pumps in during a rebuild--way too much pressure/flow, solved the problems with a 50 lb pump.
 
Thanks for the reply Alan,

I should have indicated that this is a fresh completely rebuilt motor that is balanced, bored 100 th, Isky Max 1 cam and pistons are Egge 4 ring. The oil pump is a 50 lb. pump. I have 102 miles on motor. The reason that the rebuilder placed the tubing in the drain hole was I didn't have a pipe for it at the time and the motor didn't have a pipe in the hole when I took it apart. I didn't realize what the builder had used the tubing because he built the engine to a complete engine with pan on. The tubing is 1/4 inch and the fitting was just wedged in the hole so there would have been oil coming out around the pipe plus the restriction of 1/4 inch tubing instead of the 1/2 inch pipe. Would this cause any problem with an oil leak into bell housing? After more investigation the rear main has area where oil drains down to the pipe but then also has the rope seal last before going into bell housing. In doing a search I find lots of info about rear main leaks but nothing about this vintage of motor (29A) and to whether the drain pipe being improper could cause a leak. The only oil tracks I can find are on the back of pan directly below the cork gasket. Also do I need to replace the top and bottom rope seal, or since I have not molested the upper half of sea, and motor is fresh, can I replace just the lower half, or just reuse the lower half that I removed.?
 
Well, lets start over. Does the crank have 1 slinger or 2 slingers? The 59ab crank will go into the earlier block but must use 59 aluminum seal retainer in the block and a special aluminum retainer for the early main cap. It's possible the slinger has been ground off so to use seals. The rods journal on the 59 crank is 2.139 new , not 1.9985 for the early crank. With 59 crank must use 59 rods, I think they will fit down the .100 bore. I've seen the early blocks with the 2 slingers that the builder had pushed a rope seal in the groove where the slinger goes, that's a no no. A lot of those 40-42 blocks the factory left that pipe right out of the rear main, I don't think that's your problem. After checking all this stuff it might be the cork gasket on the rear main where the pan fits against. Walt
 
Hello Walt,

The crank has 1 slinger just behind he rear main brg material and then the aluminum insert with the rope seal. The aluminum insert has the square grove in it for the rope and not the type for the slinger. Rods are 29A. I didn't see how the drain pipe could have caused the leakage problem because of the rope seal but I am not as well versed in the flatheads as a lot of you guys so I wanted to get some opinions before I put the engine back together. I am doing this work with engine in truck and really don't want to have to do this again because I made a mistake. My other question is can I replace just the lower half of rear main seal rope without replacing upper half that is still in block above crank? Thanks

Ed
 
did the builder put sealer on the cast aluminum seal before he placed in the block ? --Indian Head shellac works the best-, replacing just the lower seal works most of the time, as walt said check the gasket, they are a pain to get together some slight leakage just happens
 
Yes the builder did put sealer on aluminum before installing. Alan, Walt, I found at least most of the problem. I put solvent from solvent tank in oil pan and let sit over night and find there are some pin holes somewhere in area where pan is welded to lower bell housing and like I indicated before there were some oil tracks below the cork gasket. If I agitate the solvent in the pan it really starts dripping out the drain hole in bell housing. I cannot see the leak in pan but it is very obvious that it is somewhere between the bell housing and pan bottom near where the oil pump sits.
Thank both of you for walking me thru this oil leak search. It is a huge help having your expertise helping. Thank you very much.
Ed
 
Walt, Alan, I have a new pan and am getting ready to install the Rear Main Cap onto the engine (with engine in truck). I found no indication of any leakage from rear seal area so should I use the rear rope seal that was not leaking or do I replace with new lower seal half. I have new rear seal kit, but seal kit has a white seal and black seal. The seal that was in the cap and not leaking is a white seal. If I need to replace lower half I assume I would use the new white one? I soaked the new white seal in oil over night but it did not swell any so I don't think it absorbed much oil. Also after watching the video about replacing rear main in Holdon V8 they place a small amount of sealant on the ends of the seal where they come together and also the parting surface of the rear main. Common practice?

Also since last message I think the rear of the crank does not have a slinger per say but is a pretty conventional setup with rear thrust ridge on crank then the rope seal. The thrust surface of the bearing does have the cavity below it where the oil returns to the pan via the drain pipe.

Ed
 
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